The scalar and axial Ds mesons were expected as broad resonances above DK and $D^*K$ thresholds, but they were experimentally found as very narrow states below thresholds. In this work, we have taken into account the effects of nearby threshold on the position of these states using an ab-initio simulation for the first time. We have found that indeed the effect of threshold lowers the mass of these states and brings the mass in agreement with the experimental one. For this purpose, we have simulated DK and $D^*K$ scattering with lattice QCD, we determined the scattering phase shift as a function of energy, and extracted the scattering matrix. The resulting scattering matrix turned out to have a pole just below threshold. From the location of the pole, we determined the mass of the bound states. Both masses of the bound states were in agreement with the measured masses of Ds0(2317) and Ds1(2460). The results for the scalar meson have been already published in Phys. Rev. Lett. in 2013, while we have presented also the results for the axial meson in this work. Also, we have given a detailed account on the methodology we used to achieve this challenging physical problem. In particular, we have presented the implementation of the so-called stochastic distillation method.
COBISS.SI-ID: 2718820